Not sure where you are getting a 5505X, there is a 5506X which is the new platform. I can assure you that 9.4.2-22 will work on the ancient 5505, the 5505 began shipping in June of 2006, and stops shipping in 2017, that is pretty darn great software ...

Do you have Smartnet?Latest 5505 interim (bug fix) release was 9.2.4-22 released May 30th, 20179.2.4 base was shipped in July of 2015, but there have been many interim (bug fixes) since, and that is likely all that will come out from now on if anythi...